Fifteen years ago it was the stuff of science fiction. Now, you can just swab your cheek, send it to a company and, for only a few hundred euros, have your DNA analyzed. You’ll find out about your ancestry and your predisposition towards certain inherited diseases or conditions (from cancer and diabetes to myopia). You’ll also learn if you’re a ‘carrier’ — that is, if you’re carrying a gene that won’t affect you but might affect your children. You can even get information about more light-hearted issues like whether you’re likely to have fast- or slow-twitch muscles or your ability to taste certain bitter flavours. The technology is pretty great, but it also raises some interesting questions which I thought would be worth discussing (especially since I really enjoyed our previous discussion).

At the moment, sequencing an entire genome is still expensive enough to be out of most people’s reach. Instead, most personal genomics companies offer genotyping services. Unlike sequencing, where all three billion letters of your DNA are read, genotyping involves looking at 500,000 or a million locations in your genome. The locations are chosen because they’re close to genes known to play a role in certain characteristics or diseases or because variation at that location is statistically linked to a disease or trait. By reading a few letters of DNA at these locations, scientists can find out which variant a person has.

For example, a person with “GG” at a particular location might have a higher chance of having blue eyes, while someone with “AA” at the same location would likely have brown eyes. It’s not really that simple, though. Eye color, like many other traits, is based on lots of genes which interact to determine the actual color. It’s important to realize that genotyping doesn’t give you definite answers — you just get the odds. Knowing how to interpret those odds is important, too. You might be twice as likely as average to develop a certain disease, but if the average person has a 4% chance, your odds would still be pretty good. You’d have an 8% chance of getting the disease, meaning that 92 of 100 people like you wouldn’t actually get sick. Conditions like diabetes can also be strongly influenced by lifestyle choices. Knowing you’re at risk can help you make better decisions, as long as you understand how to evaluate the numbers.

Despite the caveats, this sort information can be quite important; it can even change your life. The actress Angelina Jolie recently decided to have a double mastectomy after a genetic test confirmed that she had a high chance of getting breast cancer. She discovered that she was carrying a mutant form of the gene BRCA1 which normally repairs DNA. The mutation made it more likely that she would develop breast or ovarian cancer, giving her odds of 87% and 50%, respectively. Based on her family history, she decided to undergo the surgery as a preventative measure. Following the operation, the likelihood of her developing breast cancer dropped to under 5%.

You’re not just learning about yourself, however. You’re also learning about your relatives, since they share some of your genome. Parents and children share 50% of their genes, as do full siblings. If you’ve got a mutated version of a particular gene, there’s a 1/8 chance that your cousin has it, too. Finding out about your own genome can mean inadvertently invading other people’s privacy. Even if you don’t tell your relatives what you’ve learned, you might change your behaviour in ways which would tip them off. Do you have the right to make that decision for them? At what point do our individual rights give way to the rights of others and communal considerations?

I think this is pretty exciting technology and I’d love to get genotyped or, better yet, have my whole genome sequenced. The question I’d like to pose is: Would you like to get genotyped or have your genome sequenced? I’m not really asking about the issues of insurance, etc, here, but we can discuss them if people want. I’m more curious about things like:

Are you interested in finding out more about where your ancestors came from and what percentage of your DNA comes from Neanderthals?

Would you just want the fun bits and none of the scary/important health-related stuff? Or maybe you’re only interested in the serious stuff?

What about incurable conditions like Parkinson’s or Huntington’s? Would you want to know if you’re more likely to develop them? Would you change your life if you were?

Given that you’re finding out for your whole family, would you ask for their consent? Do you think they should have a right to veto your decision?

What about your partner — would they get a say? Do you have an obligation to tell them about what you might pass on to your children?

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19 thoughts on “Whose genome is it anyway?”

It seems a little like peeking into your future – knowing your odds of getting certain diseases. I’m not sure I’d want to know everything, especially about the ones with no prospects for treatment or preventative measures.

However, seeing into the past is definitely something that intrigues me. I’d love to know how much of my DNA is Neanderthal. The idea of our species’ interbreeding is a fascinating glimpse into our distant past and how we came to be human. That’s a story I’d like to know more about.

I think I feel the opposite way: the untreatable conditions are the ones I would most want to know about. Maybe. If we can do something about it, I suppose it feels like it’s somehow just part of life…but if it was something incurable and debilitating, I’d want to know now so I could plan accordingly. I’m not certain that’s the right approach, but it’s how I feel at the moment.

Everyone seems to be intrigued by the possibility of finding out about their ancestry and Neanderthal heritage and I’m no exception. I sort of hope that I would have more Neanderthal ancestry than average….I guess I like the idea of carrying around an echo of the people we almost met.

I think I’d like to have my DNA analyzed. I’d like to know where my ancestors came from. I’m quite the American Mutt so that could be very entertaining. I already know I’m myopic (knew since Jr. High), but I also know I have an extra vertebrae (1 in 5 have this). But I’d like to know more like is there any DNA from Neanderthal. Why do I prefer savory over sweet?

Regarding the ethical questions: I’d like to know the bad stuff too. If I knew I had a high chance of Alzheimer’s I might begin seeking foods and teas that are good for the brain, just to stave it off as long as possible. I think I would do this for any organs or parts of my body at greatest risk.

I would get my DNA analyzed whether my family agreed to it or not. My DNA is information about me and I do have a right to it. I would only share this information with them and my wife (she most definitely has a right to that information). So I don’t think my family should worry about passing information because I won’t be putting it on Facebook or any other such nonsense. The ethical issues considered in the movie, “Gattaca” are quite yet such a huge issue, at least not from my perspective. I don’t think “now” is the time to be too paranoid about it, but I do believe that at some time in the future it will be.

I’m glad you enjoyed the post! To me, the question of sharing information with relatives becomes important in the case that they don’t want to know about certain things. I’m not really concerned about someone putting information online or more Gattaca-esque issues…but what if someone in your family didn’t want to know that, for example, they had a higher risk of Alzheimer’s? If you found out you were at high risk and changed your habits, they might pick up on it (especially if they know you’ve been tested!). I suppose I’m wondering how to handle such a situation in a way that would be fair to everyone involved.

I suppose if you discovered details about your genome, and your brother for instance, didn’t want to know, you wouldn’t have to tell him. That’s a fair enough request. But if you started seeing specialists and nutritionists, he would indeed know something is going on. I suspect that ultimately, he would change his mind and want to know what you’re doing and why.

This hypothetical brother does have the right to remain uninformed, but that doesn’t mean you cannot address the issues before you and change your life habits. That would be removing your own right to maintain your own health. I don’t see a way around it. Siblings would indeed notice life changes. It’s up to them to pursue the reasons for it or not.

Great post indeed. Personally, I would love to know my genetic ancestry in general. As for the specifics, I’d like to know everything, good or bad. However, I am saying that from the perspective that I do not think I have any horrible genetic condition. In my native Puerto Rico we have a saying that loose translated says “it is one thing to summon the devil; to see him coming at you it totally different”…

I feel the same way — I’d want to know everything, but that’s partly because I don’t expect any terrible news. (Do we ever?) I am concerned about the implications for my relatives, though, so I think I would talk it over with them first.

While writing up this post I saw that 23andme have dropped their price to only $99 (it used to be something like $400!), so I’m seriously thinking about doing this sometime soon. Of course, the next question would be: if I did get genotyped, should I write a post about the results and interpretation? :)

Just $99? Really?!?!? It is worth considering. I do not know if I’d publicize mine. I do not really know very well the laws pertaining genetic discrimination (for health insurance, etc…), and until they are crystal clear, I woild keep any results good or bad, a secret.

I happened to come across a recent article in Slate that talks about some of the issues these tests can raise for families. It’s a different set of questions than the ones I raised — and it depends on several people in a family being tested — but it’s still interesting to consider.

I was just talking to my wife about this recently but more about checking your ancestry. She was interestingly intrigued about my heritage even though I’ve considered to myself to be somewhat of a purebred (and therefore didn’t think it would be worth it). In any case, this topic is interesting to consider but I think the reality is that the technology is right around the corner and in fact although there are certainly ethical considerations, I believe almost everyone will start getting tested (fully). Personally I’m all for it. Yes it’s troubling if I have something incurable but I’d still rather know (as difficult as that might be). I’m of the opinion that the the ‘head in the sand’ attitude is usually not a good way to go. The bigger questions to society involve things like insurance, healthcare costs, and of course pre-birth screening. I haven’t seen much chatter about it yet but it seems like one of the most significant questions. We all share in the tax-burden of public health care and if genotyping (or even more detailed genomics) can give us the ability to reduce costs (by identifying and implementing preventative measures before the fact) shouldn’t everyone be _obliged_ to test their DNA?

Thanks for you comment! I hadn’t really thought about the scenario where people are obliged to get genetic tests, but I understand the reasoning now that you mention it. I don’t think it would really make a difference for uncurable conditions (say, Huntington’s), but I guess the idea would be that people who are at a high risk of developing, say, diabetes should be identified in order to take preventative measures and keep costs down. How would it work in practice? Would people lose coverage if they don’t take preventative measures? It seems like that would be hard to evaluate/enforce and would also be quite an invasion of individual autonomy.

It’s an interesting idea and I get the motivation for it, but I’m not really sure how it would work out. It’s worth thinking about & discussing, though.

I got genotyped about 20 years ago. It was for one locus, where a positive result would mean I was definitely going to get the disease which crippled my mother and contributed to her death. It’s an autosomal dominant – myotonic dystrophy. My result was negative, so were both my full-sibs’ results, so we know that we’ll not get the disease. Nor will my nephew.

For me this was a simple decision. As soon as the test became available, I wanted it. There’s no cure for the disease but I’d have known what to expect and I’d have been able to make decisions about housing, finance and so on.

Thanks for sharing your story; I can understand how having a history of a condition in the family could make the decision much more straightforward. Given your experience, I’m curious how you feel about the possibility of getting genotyped at loci associated with other conditions, since it’s now much more affordable? Do you think it’s only worthwhile if there’s a family history?

I don’t really think my opinion on this is any more valid than other people’s. It’s a personal choice. One which, as others have said in this thread, affects a whole family.

For me, genotyping with no particular target isn’t attractive. I’ve been a technician on two genome scanning projects (one about psoriasis and one about heart disease). No doubt each of those projects yielded useful information, and my name’s on an academic paper from each of them, but I got quite cynical about open-ended genome scanning. For multifactorial disorders such as cardac infarction, the advice can be summed up as ‘Eat less lard and do more sport.’ Which doesn’t change if you turn out to have a slight genetic predisposition to heart attack.

When I got genotyped for myotonic dystrophy, I was young enough not to think much about finance. But now I’d be wary because of that aspect. Whether this or that financial product would be available to me with something that could be classed as a ‘pre-existing condition’.